First impression of The RD 0198 "TL" MOD SDA 2B's

Just completed the mod. Used Gen.1 Sonicap 5.8uF in the added capacitor position. I like them already. I know they need time to break however not too bad so far. This may sound like a strange way to explain the way they sound to me but it is the best I can come up with right now so here goes. It seems as if something is missing, but it is as if that something should not have been there to start with. Does that make sense to anyone else who had done this mod. ? Need to thank @F1nut, @VR3, @westmassguy@pitdogg2 for help on this as well as many other projects I have attempted while here at CP.

Used that schematic but not the same holes as it shows so I guess there is no way to make sure I have it jumped out as it shows in the schematic. I really wish I had taken some pictures or I could see the back side of that board at "http://gimpod.com/partsp2b.html&quot; The holes I used should not matter (I do not guess) as long as I follow that schematic with my actual wiring is that not correct ?

Also, evaluation really can't be accurate until they break in. The entire speaker will change A LOT, so trying to trouble shoot now, is probably not the best.

Get 250-300 hours on them and if they still are lacking, then start trouble shooting.

But, it's always prudent to check, recheck and then recheck your work to make sure nothing was missed when doing the upgrades.

Rock on

H9

"Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass

Also, evaluation really can't be accurate until they break in. The entire speaker will change A LOT, so trying to trouble shoot now, is probably not the best.

Get 250-300 hours on them and if they still are lacking, then start trouble shooting.

But, it's always prudent to check, recheck and then recheck your work to make sure nothing was missed when doing the upgrades.

Rock on

H9

I totally agree. When I originally restored the crossovers it took quite a while for everything to settle in. It will not take all that long for me to get the 200-300 + on them as I play them more than any of the others. Elton, Sabbath, Floyd and The Grateful Dead say they sound better already.

So, today they sound like they splatter the sound. Sound a little fuzzy I suppose. After only 48 hours though...Keep in mind these descriptions are 1. Just my opinion. 2. described best I can, I am sure some of the words I use are not accurate audio descriptions.

I have some 2BTLs. During break in they never whet through a splatter phase or anything that sounded really bad. I think you need to add the jumper VR3 suggested if you used gimpod boards and check the work you did.

Did you use the original boards, or Tony's?
I prefer to use the original boards on the CRS+s due to lack of space.
On the original boards, you can forgo the jumper and just run the lead from the 5.8uf over to "H"

Did you use the original boards, or Tony's?
I prefer to use the original boards on the CRS+s due to lack of space.
On the original boards, you can forgo the jumper and just run the lead from the 5.8uf over to "H"

I used the original boards. As far as I can see it I did exactly the same as you. Only difference being my resistor leads were short so I stacked/piggybacked the resistor (2.7 ohm) on top of my capacitor. They do not touch but that was the only way to use the mills resistors that I had without extending the leads. That puts the resistor and the capacitor in parallel. If the resistor and the capacitor are supposed to be in series I have it wrong but the schematic does not call for a series run. It shows the two in parallel. far as I read it anyhow. You guys are the experts. Tell me different and I will pull them back out right now.

I still intend to go back in and check what I did. I am not going to pull them again till some break in occurs. So far, Fleetwood Mac, Three dog Night and Cheap Trick concur.

@westmassguy , Thank you Sir. I finally put two and two together after all this time and see that you are DHS. I am glad to know that now. I may get in touch about an EQ I have here made in January 1968. Unsure if I want to tackle it myself just yet.

@westmassguy , Thank you Sir. I finally put two and two together after all this time and see that you are DHS. I am glad to know that now. I may get in touch about an EQ I have here made in January 1968. Unsure if I want to tackle it myself just yet.

I do think so. He had all the cables, booklets EQ, tulip stands. Got them from a retired fellow moving to Florida. He said he wanted someone to enjoy them as much as he did all those years. He found him. January 1968 is the date on the owners manual up top right. That was the first month/year the 901's were sold from what I have read anyway.

I do think so. He had all the cables, booklets EQ, tulip stands. Got them from a retired fellow moving to Florida. He said he wanted someone to enjoy them as much as he did all those years. He found him. January 1968 is the date on the owners manual up top right. That was the first month/year the 901's were sold from what I have read anyway.

The best Equalizer for the Series I & II, is the Series II. Many improvements were made.
The 1st production model you have will be fine.

OK, took out the network and could not understand why my board was exactly like the board you posted but without an "H" on the board next to "E". The reason was revealed when I decided to pull the inductor. "H" was completely hidden under it. I understand totally the reason to jump out "E" and "H" now. If not the circuit would not be complete and the capacitor would do nothing. Using "B" and "G" for the resistor, standing it up on the board, jumping out "H" and "E" and placing the "TL MOD" 5.8uF capacitor across C5 looks like how most are doing this. With your help I do see a much better way by placing the capacitor across "R2=C5" on the top tweeter + and the "H" hole on the bottom with the resistor still at "G" and "B" is much better to me anyway. The way I did it is totally unorthodox. I used "R2"="C5" at the top tweeter + and placed the other capacitor lead in "G" with the resistor in parallel mounted on top of the capacitor because my resistor leads were too short and since I intend to re work these networks on wood one day I was not about to order new resistors twice. I suppose what I am trying to clear up is no matter what hole I use as long as the actual schematic is followed for the "TL MOD" for the SDA 2B Blade/Pin there should be no question It is right, right ? I am sorry if I was unclear in my ^ posts and thank each of you for your help and comments.

Did you use the original boards, or Tony's?
I prefer to use the original boards on the CRS+s due to lack of space.
On the original boards, you can forgo the jumper and just run the lead from the 5.8uf over to "H"

"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

LOL. ^ I keep one. Anyhow, above I had written that they had a sound that sounded sort of splattered or fuzzy. I now think that 1. some of the music I was listening was poorly recorded 2. That there were sounds in some of my music were starting to reveal themselves that I had never heard before. Like far in the background. The new tweeters are bringing out those those sounds. Everything seems very nice now. It has been 7 days of burn in at 24 hours a day now.

OK, took out the network and could not understand why my board was exactly like the board you posted but without an "H" on the board next to "E". The reason was revealed when I decided to pull the inductor. "H" was completely hidden under it. I understand totally the reason to jump out "E" and "H" now. If not the circuit would not be complete and the capacitor would do nothing. Using "B" and "G" for the resistor, standing it up on the board, jumping out "H" and "E" and placing the "TL MOD" 5.8uF capacitor across C5 looks like how most are doing this. With your help I do see a much better way by placing the capacitor across "R2=C5" on the top tweeter + and the "H" hole on the bottom with the resistor still at "G" and "B" is much better to me anyway. The way I did it is totally unorthodox. I used "R2"="C5" at the top tweeter + and placed the other capacitor lead in "G" with the resistor in parallel mounted on top of the capacitor because my resistor leads were too short and since I intend to re work these networks on wood one day I was not about to order new resistors twice. I suppose what I am trying to clear up is no matter what hole I use as long as the actual schematic is followed for the "TL MOD" for the SDA 2B Blade/Pin there should be no question It is right, right ? I am sorry if I was unclear in my ^ posts and thank each of you for your help and comments.

Did you use the original boards, or Tony's?
I prefer to use the original boards on the CRS+s due to lack of space.
On the original boards, you can forgo the jumper and just run the lead from the 5.8uf over to "H"

As long as the circuit is the same, regardless of the marking on the printed side, you're good. I frequently get creative, when trying to stuff large caps and resistors onto the old boards. That's why Tony's (@gimpod) boards are so much easier to work with.

Maybe a view of how westmassguy installed the caps and resistors on my stock boards will help. I like the way he dealt with the problem you had with the resistor. He added it to the bottom of the board.

There is no doubt now after around 225 hours or so these tweeters are brilliant. I spoke above about a splattering or fuzzy like sound. I am almost 100% that what I heard was detail starting to come in that I had never heard before. I am listening to music that I have listened to many times before and hearing sounds that I have not heard before. I have heard others say that they wish they had done the mod to start with I am in that camp now. They sound excellent !